Attachment-plug.



hereunto appended.

ATTACHMENT-PING.

Toallivhom itma e concern;

Be it known that I, IIARVEY: H BBELL, a citizen of the United States, residing at Bridgeport, county of Fairfield, State of Connecticut, have invented an Improvement in Attachment-Plugs, of which the follow ingis a specification.

The invention-relates to separable attachment plugs and has for its, object to provide'a plug of this character in which, while the connection shall be easy to' make, it shall be impossible to makeit except in one position of the contact blades. so that there can be no change in polarity. This I accomplish in themanner which I will now describe and then specifically point out in the claims In the accompanying drawing forming a part of this specification, Figure 1 is a,vie w on an enlarged scale, partly in elevation and partly in section, illustrating the construction and operation of my novel plug; Fig. 2 an elevation of one of the base contacts and the corresponding contact blade det'ached; Fig. 8 an elevation of the other base contact and the corresponding contact blade detached; Fig. I a plan view of the base detached; Fig. 5 an elevation of the cap detached, and Fig. 6 is a plan view of the cap detached. I

10 denotes thebase and 11 the cap, both made of insulating material, and 12 the.

screw shell. These partsmay be of any ordinary or preferred construction.

13 and ll denote the base contacts ivhicli lie in recesses '15- in tliebase, and 16 and 17 the contact blades which project from the cap. These contact blades are adapted to be passed through slots 18 and 19 in the base and to engage the base contacts in re; cesses 15. The ends of the contact blades are shown as rounded andbeveled for conven-' ience in engagement and as provided 011 opposite edges with recesses 20. Thebase contacts each comprise spring plates adapted to receive the corresponding contact blade between them, one plate ineach contact being provided with lugsTor indentations 21 adapted to engage the recesses 20 in thecorrespondlng contact blade.

The novelty of the present invention in the mode of making the plug non-reversible, that is, making it so that each contact blade can only be placed in engagementwith Specification of Lettersllatent.

the base contact of corresponding polarity.

With this end in view I make contact blade 16 both longer and wider thancontact blade 17 and make slot 18, which receives blade 16, la nger than slot 19 which receives blade 17 i In practice. theslots are made tojust receive the blades comfortably' The essential feature. however. is that slot 19,while receiving blade 17 freely, is made-too short to receive blade 16. In order to facilitate the-intro- ,duction of blade 16 into slot 18, I surround "Patented Apr. 25,1916.

Application filed March 15,1915. Serial N0.14,303..

the outer .end'of said slot with an elongated lnwardly tapering depression 22 which serves to guide the blade into the slot. In making the connection, blade l6 only will at first come into contact with'the base. The position of the parts may then be changed without the slightest inconvenience-even 111 the dark until blade 16 passes into the 'dem-ession and then into slot 18, after which blade 17 will pass into slot 19 as a matter of course.

Inorder to prevent abreak upon one side.

before the break occurs upon the other side in'disconnecting the members, or rather in order to make the break practically simultaneous on-both. sides, I make base contact 11 longer than contact 13 and cause it to extend farther down into the recess. In

other avords, the relatively long contact blade engages a relatively short base contact and the relatively short contact blade en 3 gages a relatively long base contact.

Having thus described my invention I claim: 4

--'1. A sepa able attachment plug comprising a base having recesses, slots leading into said-recesses, a relatively long base contact in one of said recesses, a relatively short base contact in the other recess and a cap having a relat vely long contact blade adapt ed to engage the relatively; short base contact and a relatively short contact blade adapted to engage the relatively long base contact, so that in disengaging the members "the break will be practically simultaneous on both sides. r

2. A separable attachment plug comprising a base havlng recesses, contacts in said recesses and a relatively long and a relatively short-slot leading into sa d recesses respect vely, the outer end of said longer slot beingsurrounded by an elongated inwardly tapering depressiorn and a cap having contact blades corresponding; in Width with the length of the slots, said wider blade being longer than the other blade and adapted to lira engage the depression in making contact.

3. In a sepamble attachment plug, a base havlng recesses contacts 111 said recesses and a relatively long and a relatively short slot leading mto said recesses respectively, said 10 longer slot being surrounded by an elongated. inwardly tapering depression, substantially as described. 4. an attachment plug, a cap havin a relatively long and a relatively short con tact; blade, said longer contact blade being 15 also wider than the other blade, substantially as described. a

In testimony whereof I afiix my signatm'e.

HARVEY HUBBELL. 

